3-2.1.1 Secure the test article to the test fixture in a manner that can be
exactly reproduced on subsequent units. Tighten all bolts to specification
requirements with a torque wrench. Connect and support all hoses, ducts,
cables, etc., in a manner which can be duplicated for subsequent units.
3-2.1.2 Secure the test fixture to the shaker head or auxiliary table in a
specified orientation (with respect to the shaker trunnion) and torque the tie
down bolts to specification requirements.
The test fixture shall be of rigid construction and shall be
designed to minimize low frequency resonances. To minimize the handling and
disassembly cycles required, the use of multipurpose fixtures (those
utilized for more than one test article) is not recommended.
3-2.1.3 Attach the control
accelerometer to the test fixture in close proximity to one of the test
article attachment points. The precise location shall be selected to minimize
mechanical noise feedback from the test article and resonant peaks (as
determined from prior data).
3-2.1.4 Document the complete details of the
mechanical test set-up so that they can be reproduced exactly in subsequent
tests. This documentation shall include a sketch or photographs of the set-up
plus a specification sheet which lists: the vibration equipment used, location
of control accelerometer, location and bolt torque of attachment hardware, and
identification and location of all cables, hoses and ducts connected to the
test article. A sample specification sheet (Figure
3-1) has been included which describes the equipment, etc., used in
conducting an actual test.